Smart Bubbles: Key to Israeli Aeration Energy Saving Claims

The Holy Grail of wastewater treatment is to find lower energy and cost aeration treatment. One company in Israel claims to have done that by generating bubbles that stay in the water longer. Jeremy Josephs speaks to the CEO behind the organisation and takes a closer look at an installation at the Tiberias Regional Water and Sewage Corporation.

Nov 1st, 2012

The Holy Grail of wastewater treatment is to find lower energy and cost aeration treatment. One company in Israel claims to have done that by generating bubbles that stay in the water longer. Jeremy Josephs speaks to the CEO behind the organisation and takes a closer look at an installation at the Tiberias Regional Water and Sewage Corporation.

Tiberias Regional Water and Sewage Corporation in Israel owns and operates the WWTP where the Diffusaire technology has taken place

Aeration and the production of air have been described as 'the elephant in the living room' when it comes to WWTPs. That is to say that they represent a difficult or troubling subject about which everyone present is acutely aware - but which for reasons of awkwardness all those concerned steadfastly refuse to talk about. Or, to use another analogy, there has been more than a touch of Basil Fawlty's famous one-liner when it comes to aeration costs - 'don't mention the war' - except in this instance it's been 'don't mention the electricity costs'.

When the truth is, of course, that we should be doing precisely that. Why? Because aeration is the cornerstone of biological wastewater treatment and controls the treatment performance and operational economics of the entire wastewater treatment facility. Its associated costs are thus crucial. Crucial but massive.

For energy used by WWTPs in the United States alone has been estimated to be running at ~1.5% of total US electricity consumption. Figures published by the US government's Department of Energy (DOE) show this translates to more than 3000 MW of electricity in the USA, and runs at an annual cost of over one and a half billion dollars in the United States alone.

One company claims that its modular aeration unit can provide an innovative and cost-effective series of solutions for all sized WWTPs, reducing aeration costs by anything up to 50%.

"Now, if we consider that aeration accounts for 50% of WWTPs, we are talking about the possibility of the saving of hundreds of millions of dollars worldwide, possibly even more", enthuses Meir Shimko, CEO of Israeli start-up Diffusaire.

So does this mean that this prospective solution from Israel, often dubbed the start up nation on the not unreasonable grounds that it has more NASDAQ listed companies than any other country besides the US, is all terribly high-tech?

"No, it does not", Shimko is quick to respond. "In fact that's the beauty of our system: it is high-tech but it's also terribly easy to install and, best of all, there is absolutely zero downtime. There is never any need to empty the reactor or stop the treatment process during either installation or maintenance."

Such claims throw up the question of precisely how the company's aeration system diffuses air into pumped liquids in the first place? And to which the answer is that the company has come up with a simple but devastatingly effective solution. That its bubbles are a cut above the rest. Smarter if you will. Yes, that's right - we are talking about smart bubbles.

Or, to put it somewhat more scientifically, the sad truth is that for every 40kg of air pumped through aerators only ~1kg of oxygen is actually extracted. Diffusaire's patented system actually doubles the retention time of the air bubbles in the water.

Bubbles in traditional systems ascend at a rate of approximately ten inches per second. Diffusaire's system is able to slow down their ascent - doubling their retention time, offering far more oxygen to the water and saving energy in the process. The company calls its system OTECH, a hybrid that combines air injection through diffusers against a counter flow of liquid including an innovative algorithm, constantly calculating various parameters into its decision engine.

The amount of material transferred from the gaseous phase to the liquid phase depends on several factors including temperature, concentration, contact time and boundary layer thickness. OTECH facilitates increased contact time between the gas bubble and liquid, thus allowing a greater quantity of material to pass into the fluid, the company said.

Better bubble for you buck: Diffusair says its OTECH system doubles the retention time of aeration bubbles in the water from 10 to 20 seconds

Streaming examination of the fluid against the direction of the rise of the bubbles slows the risen bubbles' velocity and increases the time of contact with the liquid. The net result of both this and a carefully positioned probe linked to Diffusaire's computer system means that you are getting far more bubble for your buck.

More marketing hype from the plucky Israeli start-up? Hardly. For Shaul David, CEO of Tiberias Regional Water and Sewage Corporation and who owns and operates the Yavniel WWTP where the Diffusaire equipment is installed is energised by the new system.

"We were very much interested in finding advanced solution to our existing aeration system which was not at all efficient and consumed high levels of energy from all perspectives - but especially in terms of electricity and ongoing expensive maintenance. We received from Diffusaire a very well-priced quotation, which we approved, and this was followed by the very speedy and simple installation of their system. We saw great results from the very first month."

The CEO goes onto add: "Now after more than two months of 24/7 operations we are entirely convinced that we have purchased from Diffusaire an efficient and advanced aeration technology which has provided us with significant savings both for electricity and O&M costs. We also really appreciate the zero down time and the fact that there was no process interruption during installation. Their ongoing technical support has been similarly impressive."

It's difficult to pin down Shimko when it comes to quantifying the precise level of energy saving likely to be encountered. Why? Because it all depends. On the size of the plant. On how well it has been maintained. On when it was built. On which treatment techniques are being used. On the size of the existing diffusers? On when they were last serviced or replaced? And so on. But his best guess - and he appreciates that he is not entirely an independent witness in these matters - is that on average a reduction in energy costs of around 50% could expect to be encountered.

That said it's clear that Diffusaire's CEO is a serious operator: he was VP of Subsidiary Operations & Global Marketing for IDE Technologies, Israel's flagship desalination company and an acknowledged world leader in the field. And it was while working for IDE that Shimko led and won two major projects in China and India, each worth more than US$100 million.

Diffusaire operates under the auspices of an umbrella incubator organization known as Kinrot Ventures - 'A Rainbow of Water Technologies' - as its publicity material puts it, and is but one of thirteen separate water technology start-ups.

Business development of Kinrot is headed up by Amit Shilony whose task it is to oversee projects ranging from the development of a micro generator that produces electrical power from water flow within pipes (Hydrospin) to a revolutionary system in remote valve monitoring for the process industry and automation world via advanced wireless technology (Eltav).

His role is that of a global bridge connecting entrepreneurs with investors and key water industry players, actively seeking out strategic and effective co-operations and partnerships. So are both he and Shimko ready to go out there, all guns blazing, so that the Diffusaire brand goes global - another start-up success on the already impressive Israeli record? Certainly not.

"It's not that we want to take things slowly", Shilony explains, "we are as keen as anyone to move things forward and get going. Because we all know that the product works. But we want to get it absolutely right.

"We are not going to go from a small plant working on 600 cubic meters a day to a system processing thousands of times that amount. We often say 'make your mistakes in Hebrew - our language here - but notch up your successes in English', or other languages for that matter."

He adds: "So if a customer from the United States or Canada comes along - and there has already been interest in both of those countries - and says 'yes, we'll take your system, thank you very much' we would be happy to put him in the pipeline for 2014. That said we are looking to expand in the next 12 months closer to home in and around the Mediterranean basin. Spain, Greece, Cyprus, Turkey, Italy, the UK, France - and so on.''

CEO Meir Shimko, formerly of IDE Technologies, estimates that energy savings could amount to up to 50%

Shimko knows that he is might well be making a mistake - interrupting his boss - but he simply can't help himself. He wishes to return to a previous theme.

"Of course no system can be all things to all men. Perhaps ours is not appropriate for huge reactors. But most reactors in the world are not so big. So for small to medium sized systems there is already no doubt that it's great. It's not just a question of saving energy. Because if you have any problem with our system you can simply hoist it out, fix it - all without closing the plant at all.

"The same for the installation of our system. With existing systems you have to close the plant, sometimes for two, three or four days - not to mention the inconvenience and environmental issues associated with emptying a reactor. With ours any repair is all over within an hour. No other system can do this. And still it's saving energy. It looks like simple engineering although actually it includes some ground-breaking innovative algorithms and is in fact a hybrid low-tech high-tech solution, plus the software which manages the programme, which we have also developed here, is of course also key."

Israel's system of technological incubators has served it well. And not just in the water sector. As massive repositories of potential ideas, the country's incubators have helped make its hi-tech entrepreneurship world-renowned.

Most striking of all, though, is that it is not at all difficult to detect the hand of the state in the form of The Office of the Chief Scientist (OCS) of the Ministry of Industry and Trade. This clearly takes great pride in implementing the government policy of encouraging and supporting industrial research and development at the very earliest stages.

In practical terms this has meant that Kinrot ventures, the water technology start-up, received 85% of its half a million dollar funding from the government, monies designed to underwrite technical innovation and enterprise but the advanced monies only becoming repayable if the business venture takes off and proves successful. It's the most public of backing for private enterprise imaginable. The net outcome of this is that Israel now boasts more tech start-ups per capita than any other country in the world.

"When it comes to ideas and innovation", Shimko muses with a mischievous grin, "the truth is that size isn't everything. When you go to the big water events around the world, yes, the major operators are always there, for sure, and so they should be. But to my mind the really interesting work, the innovation, is being displayed in the smaller booths and exhibition stands. Not exactly on the sidelines. But when your idea is new to the market it can of course take time to penetrate.

"When it comes to diffusers the prevailing mentality has been 'if it ain't broken, don't fix it' - even when you can demonstrate that there are huge savings to be made. There is a natural conservatism in the industry, which is often slow-moving, and this is something we are constantly fighting against, for sure. It was the same thing when the car was invented. Some people turned round and said 'what do we want that for - what we really need is faster horses.'

"But we are passionate about our product. We know that it works. And we really do feel that our system of smart bubbles are really going to fly."